The competitive community abandoned Reforged. W3Champions maintains a dedicated 1.31 client for ladder play.
For those with a CD install (version 1.07-1.27): Warcraft 3 Frozen Throne Patch 1.31 Download High Quality
Launch Frozen Throne.exe. On the main menu, look at the bottom right corner. You should see version number 1.31.1.12164. The competitive community abandoned Reforged